At least 36 people were killed when a bus collided with a truck on an expressway in eastern China, authorities said Sunday.

A bus with 69 people on board crossed into the opposite lane and hit the truck on Saturday morning, the Yixing city information office said in a social media post. Initial investigation indicated a flat tire on the bus was the cause, the post said.

Another 36 people were injured, including nine seriously, the Yixing government said. Three people were riding in the truck.

Yixing city lies west of Shanghai in Jiangsu province, near China's east coast.